Electromagnetic contactor



May 11, 1965 J. F. DRIES ELECTROMAGNETIC CONTAGTOR 5 Sheets-Sheet 1 Filed NOV. 17. 1960 J. F. DRIES May 11, 1965 5 Sheets-Sheet 2 Filed Nov. 17. 1960 y 11, 1965 J. F. DRIES 3,183,409

ELECTROMAGNETIC CONTACTOR Filed Nov. 17. 1960 5 Sheets-Sheet 3 5 a? I E- May 11, 1965 J. F. DRIES 3,183,409

ELECTROMAGNETIC GONTACTOR I Filed Nov. 17. 1960 5 Sheets-Sheet 4 y 1, 1965 J. F. DRIES 3,183,409

ELECTROMAGNETIC CONTACTOR Filed Nov. 17. 1960 5 Sheets-Sheet 5 removed from the panel.

United States Patent This invention relates to electro-magnetically operable contactors, and particularly to a compact contactor which can be easily disassembled for maintenance and repair.

Contactors of the type contemplated herein are assembled into unitary structures which are secured to a control panel. Generally, the contactor is supported on the control panel by supporting and terminal screws located on the back of the panel. In order to repair or replace any partsin the contactor, a work space must be provided behind the panel so that the contactor can be The contactor must then be completely disassembled to repair or replace any of the parts.

The primary object of this invention is to conserve control panel space requirements and maintenance time Another object is to provide a contactor demountable from the front of a control panel in which the component parts of the contactor can be readily disassembled for repair or replacement.

These objects are accomplished by providing terminal stud connections in a position on the front of the control panel where they can be readily connected to the contactor. The position of the terminals with respect to the control panel will depend on whether the bus bars are to be located in front of the mounting plate, behind the mount-ing plate or behind the control panel. In all of these positions, a novel arrangement of insulating blocks are used to support the terminal studs so that the contactor can be removed from the front of the control panel.

Once the contactor is removed from the panel, it can be readily disassembled by releasing a number of simple locking arrangements.

Other objects and advantages will be pointed out in, or be apparent from, the specifications and claims, as will obvious modifications of the three embodiments shown in the drawings, in Whi ch:

FIGURE 1 is a side elevation of the contactor with the terminals removed;

FIG. 2 is a front elevation with terminal attached;

FIG. 3 shows the spring look arrangement for the arc shield;

FIG. 4 shows the pin lock arrangement for the armature lever;

FIG. 5 shows a terminal arrangement when the bus bars are located in the front of the mounting plate;

FIG. 6 shows the terminal arrangement when the bus bars are located behind the mounting plate;

FIG. 7 shows the terminal with the bus bars located behind the control panel; I

FIG. 8 is taken on line 8+8 of FIG. 1 showing the arc horn and are shield arrangement;

FIG. 9 shows the insulator blocks for the terminals when the bus bars are in front of the control panel;

FIG. 10 is a projection of the armature lever and movable contact; and

FIG. 11 is an exploded view of the contactor with the armature lever removed.

As seen in the drawings, the contactor includes a stationary contact 10 and a movable contact 12- positioned within an arc shield 14 which supports are horn .16 contoured to correspond to the curvature of the top or" the movable contact. The movable contact is secured to Y arssass Patented May 11, 1965 ice contact lever 18 pivoted on shaft 20 on armature lever 22 which is pivoted on pin 24 in magnet frame 25. On energiZat-ion of coil 26, an electro-magnetic field will be set up in core 2 8 which will attract the armature lever rotating it on pin 24 in a clockwise direction bringing contact post 12 into engagement with contact post 10. The contacts will engage before the armature lever has moved into engagement with the core, so that the final motion of the armature lever will cause contact lever 18 to rotate counterclockwise on shaft 2%) compressing spring 3% to bias contact 12 against contact 10, thus, assuring positive engagement between the contacts. When the coil is deenergized, spring 34 will initiate a counterclockwise motion in the armature to release the armature from any residual magnetism that may remain in the core. The armature lever will continue to rotate due to its own Weight, breaking the engagement of the posts. The are resulting from the disengagement of the contacts will be picked out by the arc horn and the interior surface of the arc shield attenuating the are, so that it will cause no harmful effects when it is released from the shield.

The magnet frame and core are secured to a mounting plate 34 by screws 36 and 33, respectively, with insulator 40 positioned between the magnet frame and mounting plate to insulate the frame from the plate. The screws are insulated from the plate by an insulator block 42 having a boss 44 that projects through the plate into a pressfit insulating washer 46. Discs 4% are inserted into the open end of the insulator blocks to enclose the heads of the screws. This arrangement completely insulates the mounting plate from the magnet frame. The coil is of the encapsulated type with terminal connections 52 provided on either side of the coil for connection to a suitable power source (not shown). The coil fits on the core which is spaced away from the magnet frame by a nonmagnetic washer 54 of a predetermined thickness and is held in position by spring clip 56 which is seated in annular groove 58 near the end of the core. The clip has a tapered aperture 59 which is wide enough at one end so that it can be positioned on the core and narrow at its other end for alinement in groove 58 when the clip is pushed downward on the core. The clip has a pair of downwardly bent tabs on at the wide end which overlap the edge of the coil when the aperture of the clip is alined with the groove in the core. The clip is slightly curved to provide a bias against the coil holding it in position on the core. It can be seen that by merely pulling the tabs 60 free of the coil and sliding the clip upward, the clip and coil can be removed from the core.

The armature lever is pivoted on pin 24 and supports the contact post lever at its upper end and an interlock mechanism 62. (shown generally) at its lower end. Pin 24 is slidable into aperture 64 in the magnet frame and aperture 66 in the armature lever. A cross pin 70 is looped around screw 72 in the magnet frame with the straight end of the cross pin extending into hole 68 in pin 24. Screw 72 is then tightened in the frame to lock the cross pin in position. The pin 24 will then be held in position and can only be removed by loosening screw 72 and sliding the cross pin out of aperture 68. With screw 72 loosened and pin 7% withdrawn from aperture 68 the looped formation, pin 76 retains it on the shank of screw 7 2. The movable contact post has a terminal connection 74 which can be secured to one of the terminal lugs as described hereinafter.

The stationary contact is mounted on a contact post assembly '76 which is secured to the mounting plate by screws '79 and 80 insulated from the plate by blocks 42, washers 46 and discs 4-8. The are chute or are shield 14 is split and is pivoted on pin 78 and held together by screws 81. A leaf spring 82 (FIG. 3) is secured to the contact post assembly and passes through an aperture s a 84 in L-bracket 86 secured to the side of the arc shield. Spring 82 normally acts to hold the arc chute in the positlon shown in FIG. 1. The are chute may be pivoted upwardly on the pin 7 3 against the downward bias of spring 82 and a bent portion 88 of the latter limits the upward movement of the arc chute. A terminal connection W is provided on the contact post assembly which is also attached to the terminal lugs as described hereinafter. I

The present contactor can be adapted for use with bus bars located in front of the mounting plate, in front of the control pane1,or behind the control panel, all of which constructions will next be described. ,When the mount ing plate is secured to control panel 112 by screws 11 with the bus bars located in front of the mounting plate (FIG. 5) an integrally molded insulator llhtl is secured to the mounting plate by screws 1G8. Threaded inserts 162 are molded into the insulator to support terminal lugs 104, 1% which project above'the top surface of the mounting plate. The terminal lugs are screwed into the inserts and contactor terminals '74 and 90 secured thereto by nuts ill). A bus bar (not shown) is secured to each terminal lug between the nut 110 and a lock washer and nut which is threaded on the lug and tightened down on the lead and bus bar. The contactor assembly can be easily removed from the control panel by loosening the nuts on the terminal lugs to release the bus bars and unscrewing screws 114.

When the bus ,bars are located behind the mounting plate (FIG; 7) but in front of the control panel, the terminal construction shown inFlG. 9 is employed. In this construction, molded insulator blocks 12h having threaded inserts 122 molded therein are flattened on one side for retention in bracket 124 secured behind the control panel by screw 126. The insulator blocks have a boss 128 which extends through the control panel and cooperateswith a recess 130 in another insulator block 132 having a central aperture 134 through which theterminal shoulders andrecesses of insulator blocks 120 and 132 provides an electrical creepage barrier between the studs 164 and 1% and the mounting plate. The two insulator blocks cooperate to insulate the terminal studs completely from the control panel. Nuts 136 are staked to the terminal studs to limit the extent to which the studs can be-screwed into the insulator blocks. A thin frangible dome 13$ closes the lower end of the threaded hole in block lid to insulate the end of the lugs from the bracket. When the terminal lug is thus screwed into the two insulator blocks, they will be clamped on the control panel and the bus bars 139 connected to the terminal stud between the nuts 136 and washers 149 and nuts 142. The contactor mounting plate is secured to adapter 156 secured to the control panel by screws 114 to elevate the mounting plate above the surface of the control panel to accommodate the bus bar. The terminal studs project above the mounting plate and each such upwardly projecting portion of the terminal stud has a positioning nut 146. A lock washer 148 is mounted on the lug above the staked nut and the terminal leads 74 and 90 are connected to the respective stud by tightening nut 150 down on the washer. In this arrangement, front panel removal is accomplished merely by removing nuts h holding the terminal leads and screws 114 holding the mounting plate .on the adapter. w

If the bus bars are located behind the control pane (FIG. 6) the same two blocks (FIG. 9) described above may be used to insulate the terminal lug from the main panel. However, since the terminal lug must in this construction extend behind the main panel for connection to the bus bars, the nut 136 is staked on each terminal stud so that the terminal stud can be screwed through block 12f), pushing the frangible dome 13% out of the bottom of the block. The terminal stud will project bebind the control panel so that the bus bars can be connccted to the lugs between nuts 152' and 154. The mounting plate is secured to the main panel and the contactor terminals 74 and 9tlsecured to the terminal studs in the manner described above. It will be apparent from FIGS. 6 and 7 that in'these mounting arrangements, that the contactor can be removed and replaced without dislocating the bus bars and the mountings thereof.

Although but three embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention orfrom the scope of the appended claims. j

I claim: t 1. An electromagnetic contactor attachable to and removable from the front of a control panel by perform- 7 means operable from the front of said mounting plate forsecuring said mounting plate to the front of said panel; terminal stud means mounted adjacent said mounting plate and extending away from said panel to connect with said power terminal means; and means operable from the front of said contactor for fastening said terminal stud means to said power terminal'means.

2. An electromagnetic contactor attachable to and removable from the front of a control panelby performing attachment and removal work solely in front of said contactor and panel'conrprising a contactor assembly including a pair of contacts, a pair of power terminals, and an electromagnet; a mounting plate; means for attaching said contactor assembly to said mounting plate and electrically insulating said contactor assembly therefrom;

means operable from the front of said mounting plate for securing said mounting plate to the front of said panel; power current carrying means mounted on and insulated from said panel including connecting means extending away from said panel to connect with said power terminals; and means operable from the front of said contactor for fastening said connecting means to said power terminals. v

3. An electrical control panel assembly with an electromagnetic contaetor attachable to and removable from.

the front of a control panel by performing attachment and removal work solely from in front of said contactor and panel comprising a panel; a contactor assembly including a pair of contacts, a pair of power terminals, and an electrornagnet; a mounting plate; means for attaching said contactor assembly to said mounting plate and electrically insulating said contactor assembly therefrom;

said panel and away from the front of said panel to electrically connect with said, power terminals; and means operable from the front of said contactor for fastening said terminal connecting means to said power terminals.

4. An electrical control panel assembly with an electromagnetic contactor attachable to and removable from the front of a control panel by performing attachment and removal work solely from in front of said contactor and panel comprising a panel; a contactor assembly including a pair of contacts, a pair of power terminals, and an electromagnet; a mounting plate; means for attaching said contactor assembly to said mounting plate and electrically insulating said contactor therefrom; means operable from the front of said mounting plate for securing said mounting plate to the front of said panel; power current carrying wiring means mounted in front of said panel and behind said mounting plate and electrically insulated from both; terminal connecting means mounted on and insulated from said panel extending away from the front of said panel to electrically connect with said wiring means and extending further from the front of said panel to electrically connect with said ower terminals; and means operable from the front of said contactor for fastening said terminal connecting means to said power terminals.

5. A terminal stud and insulator assembly for an electromagnetic contactor adapted to be secured to the front of a control panel comprising a first insulator block having a boss insertable from the back of said panel through an aperture in said panel for projection through said panel, a second insulator block having a recess adapted to receive said boss, a threaded terminal stud, said first and second blocks having a lined apertures for supporting said stud, said first block having threaded means therein for engaging said stud, and means secured to said stud for limiting the depth of penetration of the stud into the block when inserted from the front of said panel.

6. The invention as defined in claim 5, wherein said first insulator includes a frangible closure means which is left in said first block when said stud is connected to power lines in front of said blocks.

7. The invention as defined in claim 5, wherein said first insulator block includes a frangible closure means which is forced from said first block by said terminal stud when said stud is connected to power lines in back of said control panel.

8. The invention as defined in claim 5, wherein an elastic insulating sealing ring is seated between said first and second insulator blocks'about said stud to provide an electrical erecpage barrier between said stud and said panel.

References Cited by the Examiner UNITED STATES PATENTS 2,314,225 3/4-3 Leece 3l7-120 2,412,259 12/46 Graves 317-118 2,424,308 7/47 Ellis et a1. 20087 2,632,075 3/53 Rawlins et a1. 200l47 2,727,111 12/55 Pokarny 200-147 2,943,244 6/60 Platz et al. 317-119 2,986,676 5/61 Edmunds 3171 19 JOHN F. BURNS, Primary Examiner. MAX L. LEVY, Examiner. 

1. AN ELECTROMAGNETIC CONTACTOR ATTACHABLE TO AND REMOVABLE FROM THE FRONT OF A CONTROL PANEL BY PERFORMING ATTACHMENT AND REMOVAL WORK SOLELY IN FRONT OF SAID CONTACTOR AND PANEL COMPRISING A CONTACTOR ASSEMBLY INCLUDING A PAIR OF CONTACTS, POWER TERMINAL MEANS, AND AN ELECTROMAGNET; A MOUNTING PLATE; MEANS FOR ATTACHING SAID CONTACTOR ASSEMBLY TO SAID MOUNTING PLATE AND ELECTRICALLY INSULATING SAID CONTACTOR ASSEMBLY THEREFROM; MEANS OPERABLE FROM THE FRONT OF SAID MOUNTING PLATE FOR SECURING SAID MOUNTING PLATE TO THE FRONT OF SAID PANEL; TERMINATING STUD MEANS MOUNTED ADJACENT SAID MOUNT-, ING PLATE AND EXTENDING AWAY FROM SAID PANEL TO CONNECT WITH SAID POWER TERMINAL MEANS; AND MEANS OPERABLE FROM THE FRONT OF SAID CONTACTOR FOR FASTENING SAID TERMINAL STUD MEANS TO SAID POWER TERMINAL MEANS. 